Fault in Radio Communication Line
The vehicle's computer has detected a problem with the radio communication circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The vehicle can't communicate properly with the radio system, often due to bad wiring or a faulty radio itself.
What the computer is actually seeing
The computer monitors the communication signals on the radio circuit. If it sees signals are out of expected range (like voltage levels not between 0.5V to 4.5V), it sets this code.
What a healthy reading looks like
Signal levels for the radio should be between 0.5V (off) and 4.5V (full on), with stable readings when the radio is functioning properly.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect the wiring and connectors for the radio for any visible damage or corrosion. If found, repair or replace as necessary.
- 22. Check the voltage at the radio connector with the key on (engine off). Look for 12V on the power feed. If not present, trace back to the fuse or relay and fix.
- 33. With the radio powered on, monitor the communication signal on the data line with a multimeter or oscilloscope. It should fluctuate between 0.5V and 4.5V. If it doesn't, replace the radio unit.
Common causes
- Loose or corroded wiring connections
- Faulty radio unit
- Poor ground circuit for the radio
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive the vehicle with this code?
Yes, it is safe to drive, but you won't have radio functionality until fixed.
Will this code come back after clearing?
It can return if the issue is not resolved, like faulty wiring or a broken radio unit.
Why does this code sometimes pair with other B codes?
It can indicate related systems (like steering wheel controls or climate control) are affected by the same communication failure.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
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